Motor base



Aug. 1,1939. v E. s. BARGER. 2,167,793

MOTOR BASE Filed March 15,1958

lg] v 1 VLTTI v q INVENTOR I I /0 27 /6 27 6V0 7 ATTORNEYS- PatentedAug. 1, 1939 UNITED STATES PATENT OFFICE Claims.

This invention relates to improvements in motor bases, and moreparticularly to a novel base for the support of a motor having a drivingbelt, the construction being such that the belt of 5 the motor will betight while the motor is running, and the tension on the belt will beslacked away when the motor is idle.

An object of my invention is to provide an improved motor base for thepivotal support of a motor which will provide dampening means for takingup the shock or impulse produced when the motor is started or when theload is thrown on or suddenly increases. Another object of the inventionis to provide a novel base for the support 1 of an electric motorcomprising a platform mounted off-center on a transverse pivot andprovided with a plurality of air cushioning or dampening pistons andcylinders which will operate to effectively cushion and dampen anyvibration from the motor either in starting or in running, or from anychange in the load on the motor and the belt connected with the workwhich the motor is driving.

A further object of the invention is to provide an improved torque andvibration damper for motor bases, which will be highly efficient inoperation, and quite inexpensive to produce. A still further object isto provide a motor base of the above character having means whereby thepivotal movement in a true vertical plane is as-.

sured and lateral angular displacement, with resuiting misalignment,effectively prevented.

With the above and other objects in view,

which will appear as the description proceeds, the

invention resides in the combination and arrangement of parts and in thedetails of construction hereinafter described and claimed, it beingunderstood that changes in the precise embodiment of the inventionherein disclosed, may

be made within the scope of what is claimed,

without departing from the spirit of the invention.

In the accompanying drawing which forms a part of this specification,

Figure 1 shows in longitudinal section, a device constructed inaccordance with the invention, a motor being mounted thereon;

Figure 2 is a top plan view of the base alone, the motor being omitted;and

Figure 3 is a transverse section through the base.

Like characters of reference are used throughout the followingspecification and the accompanying drawing to designate corresponding 7parts.

place. 10

Cross bars 6 are located at the ends of the side beams 2 of the supportI, underneath the flanges 3, being fastened to the flanges 3 by securingelements I, to tie the side beams together.

The device comprises a table or platform 8 15 which has pivotal verticalmovement with respect to the support I. table 8 includes side beams 9,shown as angle members having vertical, parallel depending flanges Hiand horizontal, inwardly extended flanges I II. The flanges III of thetable. 20 8 flt closely but slidably between the flanges 4 of thesupport I and extend the full length of the table. The flanges I I ofthetable'or platform have elongated slots I4. Cross bars I5 extendunderneath the flanges II, at the ends of the 5 table 8 and are securedat I6 to the flanges II to tie the beams 9 together. A pivot member II,shown as a rod, extends through the flanges 4 of the side beams 2 of thesupport I and through the adjacent flanges III of the side beams 9 ofthe 30 platform 8. The flanges III of the table are cut away from theirends, toward a point beneath the pivot member I1, as shown at I2, tofacilitate the tilting movement of the platform 8 with respect to thesupport I.

Air cushion mechanisms or dash pots are interposed between the platform8 and the support I. There-may be any desired number of these aircushion mechanisms, four being shown, located two at each end of thebase. These air cushion 40 mechanisms comprise cylinders I8 secured tothe cross bars 6, and pistons fitting therein. The pistons illustratedin the cylinders l 8 at the right hand end of the support, as viewed inFigure 1 are provided with downwardly presented cups 5 or leatherpacking elements which when forced into the cylinders I8 serve tocompress the air and thus cushion or retard the downward movement of thetable at that end. 1 The pistons 26 located in the cylinders I8 at theopposite end of 50 the support are provided with upwardly turned leathercups or packing elements and exert only asmall amount or no dampeningeffect when the pistons are moved downwardly in the cylinders. When thepistons are moved upwardly 55 in the cylinders, however, they tend toform a vacuum below themselves, and thus act to dampen or retard suchmovement. The stems 20 of the pistons l9 and 26 are secured at 2! to thecross bar ii of the platform. Minute air passages or restricted vents 21are formed in the walls of the cylinders l8 adjacent the lower endsserve to slowly admit air or to slowly permit the air to escape, as thecase may be.

As clearly illustrated in Figures 1 and 2, the transverse pivot memberII, preferably a rod extending between and through the side flanges ofthe support and the adjacent said flanges of i the platform, ispositioned considerably more for adjustment.

- electric motor in starting,

It will be noted that the motor is mounted off-center on the platform,that is to say, the center of gravity lies to. one side of the pivot l1.Thus the weight of the motor tends to turn the platform about its pivotin a clockwise direction, or toward the right as viewed in Fig. 1, thusmaintaining the belt 24 extended.

The mode of operation of my improved motor base is as follows:

The motor 22 is secured to the table, as illustrated in the drawing, andthe belt 24 placed over the pulley 23, and also over the work to bedriven by the said motor. It is a well known fact that when the electriccurrent is applied to an there is always a jerk due to the reaction fromthe torque, and the same is true when the load is first thrown on. Thismovement or jerk is of course, in a direction opposite to the directionof rotation of the motor shaft. In order to realize the advantages ofthe present invention, there must be a definite rela-- tion between 'thedirection of rotation of the motor' shaft, the direction in which thebelt extends, and the side of the pivot on which the center of gravityof the motor lies. The arrow shown in Fig. 1 of the drawing indicatesthe direction of rotation of the. motor shaft. The reaction from thetogua'when the load comes on, will of course, tend to tiirn the motorframe in the opposite direction, that is to say this reaction will tendto rock or tilt the platform 8 in a clockwise direction, or toward theright as viewed in Fig. l.

From the foregoing description, it will now be understood that thecharacter of the cup leathers l9 and 26, and the manner in which theyare formed, are such that they both simultaneously tend to stronglyresist this right-handed pivotal movement of. the platform, the cupleathers l9 resisting by virtue of thefact that they compress the airbeneath them, and the cup leathers 26 resisting by reason of the reducedpressure created below them. As these pistons or cup leathers move underthe influence of the reaction fromv the torque of the motor, the airslowly escapes from the restricted vents 21 under the pistons l9, and isslowly drawn in tofill the partial vacuum created under the pistons 26.Thus all of these thereof, and

pistons and cylinders act as dash pots to retard or dampen the pivotalmovement of the platform 8 in the direction in which it moves under theinfluence of the torque reaction of the motor. Thus when the motor isstarted or when a load is suddenly thrown on it, the resulting pivotalmovement of the platform takes place slowly and evenly, because of thechecking action of the cylinders and pistons above described, and theoperation of the motor .is thus rendered extremely steady and stable.

It will also be noted that while the weight of the motor normally tendsto rock the platform about its pivot in such a direction as to maintainthe belt 24 extended, when the load comes on the motor the torquereaction tends to turn the platform further in the same direction, thusautomatically increasing the tension on the belt.

When the supply circuit is opened, or when the load is thrown off of themotor, this force tending to rock the platform and tighten the belt isdiminished, and the belt therefore slackens,

but it will be noted that this return pivotal movement of the platformis preferably not checked or dampened by the dash pots, but is allowedto take place substantially freely. The movement is dampened only as theload comes on.

It will be understood that the checking or retarding of the rockingmovement of the platform by the dash pots as the load comes on the motoris of a wholly different nature from theresilient effect produced-bysprings or closed air cushions. Such resilient devices would tend toproduce a rebound, which is very objectionable. With the air cylindersprovided with restricted vents as shown, I obtain a steady retarding ordampening action which wholly prevents undesired vibration oroscillation of the motor. By the term dash pot as used in the claims, Itherefore intend to mean a fluid controlled cushioning device in whichmeans such as a restricted by-pass or bleed port are provided forpermitting the slow passage or escape of fluid, inwardly or outwardly,when force is applied.

By reference to Fig. 3, itwill be noted that the flanges 4 and IIIwhich, as above described, lie closely adjacent each other in verticalplanes, constitute parallel bearing surfaces which extend a substantialdistance on both sides of the pivot l1 and which serve to guide thepivotal movement of the platform and ensure such movement being confinedsubstantially to a vertical plane. The interengagement of these flangesor bearing surfaces serves to prevent any lateral. angular displacementof the platform, with resulting misalignment of the motor. I regard thisas also constituting an important feature of the invention.

Many minor changes in detail of construction may be resorted to withoutdeparting from the spirit of the invention.

I claim:

1. A motor base comprising a platform mounted for pivotal movement aboutan axis parallel with the motor shaft, means for securing I a motor tosaid platform, and dash pot means for retarding oscillatory movement ofsaid platform about said axis.

2. A motor base comprising a platform mounted for pivotal movement aboutan axis parallel with the motor shaft, means for securing a motor tosaid platform, and dash pot means for dampening oscillatory movement ofsaid platform about said axis substantially in one direc tlon only.

3. A motor base comprising a platform mounted for pivotal movement aboutan axis parallel with the motor shaft, means for securing a motor tosaid platform, and a single acting dash pot connected with a fixedsupport and with said platform for retarding its pivotal movement in thedirection in which it tends to turn due to the-reaction of the armaturetorque-- 4. The combination with a motor having a driving pulley, and abelt on said pulley, of a motor base comprising a pivotally mountedplatform, means for securing the motor to said platform in a position atone side of the pivot, so that the weight of the motor tends to turn theplatform in a direction to maintain said belt extended, and dash potmeans for retarding the pivotal movement of the platform in that direcvtion.

5. The combination with a motor having a driving pulley, and a belt onsaid pulley, of a motor base comprising a pivotally mounted platform,means for securing the motor to said platform in a position' at one sideof the pivot, so

that the weight of. the motor tends to turn the platform in a directionto maintain said belt extended, the direction of rotation of the motorbeing such that the reaction due to the torque, when the load increases,tends to turn the platform further in the same direction as the weightof the motor tends to turn it and thus tighten said belt, and dash potmeans for retarding the pivotal movement of the platform in thatdirection.

ELBERT S. BARGER.

